1. Field of the Invention
The present invention relates to a method for producing an ink jet recording head, and to an ink jet recording method produced by such method.
2. Related Background Art
The ink jet recording head, employed in the ink jet recording method (liquid jet recording method), is generally provided with a fine recording liquid discharge port (hereinafter called orifice), a liquid flow path and a liquid discharge energy generating portion provided in a part of the liquid flow path, all in plural units. As one of the conventional methods for producing such ink jet recording head, the Japanese Patent Application Laid-open No. 61-154947 discloses a method forming a liquid flow path pattern with soluble resin, then covering such pattern with epoxy resin or the like, hardening the covering resin, and eliminating the soluble resin pattern by dissolution after the substrate is cut.
On the other hand, the material constituting the liquid flow path of the ink jet recording head is required to have a high mechanical strength as the structural material, satisfactory adhesion to the substrate, satisfactory ink resistance and a high resolving power for forming a fine pattern of the discharge ports.
However, with the recent progress in the ink toward higher performance, it is being found sometimes difficult to meet all these requirements, and the peeling from the substrate is sometimes encountered particularly in case of a long-sized head or the like. Also meeting all these requirement may limit the selection of the material itself and may reduce the tact at the manufacture.
Separately, the periphery of the discharge port preferably has ink repellent property, but such property is provided by an ink repellent layer formed around the discharge port and is generally deficient in the abrasion resistance and in the adhesion to the substrate. It is also possible to form the flow path forming member itself with an ink repellent material, but, in such case, the interior of the liquid flow path has to be made hydrophilic. As a method for hydrophilizing the interior of the flow path, the Japanese Patent Application Laid-open No. 6-191036 discloses a method of forming the wall of the liquid flow path with water repellent resin and hydrophilizing the internal surface of the liquid flow path for example by an ashing process.
The method disclosed in the Japanese Patent Application Laid-open No. 6-191036 will be outlined with reference to FIGS. 10A to 10I.
In order to stabilize the ink discharge direction and to improve the durability, a liquid flow path end forming groove 103 is provided on a substrate 101 as shown in FIG. 10A, and a water-repellent settable resin layer 105 is formed therein as shown in FIG. 10B. Then a belt like-shaped solid layer 106 composed of soluble resin is formed thereon, and a water-repellent settable resin layer 113 is coated thereon as shown in FIG. 10C, and a top plate 107 is placed as shown in FIG. 10D. Then, as shown in FIG. 10E, the pattern of the water-repellent settable resin layer 113 is hardened by the irradiation with active energy ray, and an unhardened portion 113a is removed as shown in FIG. 10F to form a part of a liquid chamber 114. Then cutting is executed along the position of the water-repellent settable resin layer 105 shown in FIG. 10F to form a discharge port face 119 as shown in FIG. 10G, and the aforementioned solid layer is dissolved out to form a liquid flow path 115 and a discharge port 116 as shown in FIG. 10H. Then, as shown in FIG. 10I, the liquid flow path 115 and the liquid chamber 114 are subjected to a hydrdophilizing process to form a hydrophilic film 117. In this manner, the discharge port face 119 can be composed of water-repellent settable resin of a uniform material.
However, such method is difficulty in control in order to obtain uniform hydrdophilicity on the internal wall to be hydrophilized.
In consideration of the foregoing, an object of the present invention is to provide a method for producing an ink jet recording head, capable of avoiding peeling of the flow path forming material from the substrate even in case of a long-sized head, and enabling satisfactory range of material selection and satisfactory productivity.
Another object of the present invention is to provide a method for producing an ink jet recording head showing excellent durability of the hydrophilic film in the liquid flow path and of the water repellency on the discharge port face.
The above-mentioned objects can be attained, according to the present invention, by a method for producing an ink jet recording head, comprising steps of:
forming, on a substrate, a solid layer consisting of soluble resin and having a pattern to constitute a liquid flow path;
forming an inorganic film by low temperature film formation so as to cover the solid layer;
forming a layer of a material constituting the head so as to cover the inorganic film;
removing a part of the inorganic film in order to form a discharge port; and
removing the solid layer to form a liquid flow path communicating with the discharge port.
In such method, the layer of the head constituting material may be composed of an ink repellent material to achieve uniformity of the interior of the flow path at the same time.